Effect of gefapixant on the pathogenesis of chronic cough

JRCT ID: jRCT1041230149

Registered date:07/02/2024

Basic Information

• Recruitment status: Recruiting
• Health condition(s) or Problem(s) studied: Refractory chronic cough
• Date of first enrollment: 07/02/2024
• Target sample size: 40
• Study type: Interventional
• Intervention(s): Gefapixant (Rifnua Tablets 45 mg) is administered orally at a dose of 45 mg twice daily for 8 weeks.

Outcome(s)

Primary Outcome

1 Change in cough threshold (= concentration of capsaicin solution that elicited over 5 coughs) from baseline at 4 weeks
2 Change in number of bronchial smooth muscle contraction-induced coughs from baseline at 4 weeks

Secondary Outcome

1 Leicester Cough Questionnaire (LCQ)
(a) Change from baseline at 4 weeks of treatment.
(b) Proportion of patients achieving a minimum clinically meaningful change (MCID) of 1.3 or more from baseline at 4 weeks of treatment.
2 Newcastle Laryngeal Hypersensitivity Questionnaire (J-NLHQ)
(a) Change from baseline at 4 weeks of treatment.
3 Hull Airway Reflex Questionnaire (HARQ)
(a) Proportion of patients scoring 13 or more at 4 weeks of treatment
(b) Change from baseline at 4 weeks of treatment
4 Cough Visual Analogue Scale (Cough VAS)
(a) Change from baseline at Treatment Week 4
(b) Proportion of patients achieving an improvement of at least 15 mm from baseline at dose 4 and with a cough VAS of less than 40 mm
5 FSSG
(a) Change from baseline at Treatment Week 4

Key inclusion & exclusion criteria

• Age minimum: >= 20age old
• Age maximum: Not applicable
• Gender: Both

Include criteria

1 Men and women aged 20 years or older at the time of consent.
2 Patients with "refractory chronic cough" for whom gefapixant is indicated (specifically, patients whose cough persists despite adequate treatment based on a comprehensive diagnosis including medical history, occupation, environmental factors and clinical examination results that cause chronic cough, referring to guidelines, etc.).
3 The patient's free written consent to participate in the study has been obtained after sufficient informed consent.

Exclude criteria

1 Patients with a history of hypersensitivity to any component of gefapixant
2 Patients with hypersensitivity to sulphonamides
3 Patients with eGFR less than 30 ml/min/1.73 m^2
4 Pregnant or possibly pregnant patients
5 Nursing mothers
6 Patients on gefapixant (can be included if they have been using it for at least 4 weeks after discontinuation)
7 Patients with a history of upper or lower respiratory tract infection within 4 weeks of previous observation
8 Patients with a fever of 37 Celsius or higher
9 Patients on the following drugs and therapies
Central antitussives (e.g. Codeine phosphate, herbal medicines with antitussive properties)
Neuropathic pain medications (e.g. Opioids, gabapentin, pregabalin) and amitriptyline
ACE inhibitors
Anticholinergic and anticholinergic drugs (e.g. Tricyclic antidepressants)
SMART therapy (Symbicort maintenance and reliever therapy. This therapy uses a combination of the inhaled steroid budesonide and the long acting beta2 stimulant formoterol as a long term control for asthma as well as a treatment for asthma attacks).

Related Information

• Primary Sponsor: Hara Johsuke